Autoantibodies against oxidized LDL. A potential marker for atherosclerosis

Oxidized LDL, not the native LDL, promotes atherosclerosis. However, ox-LDL is usually undetectable in the blood circulation. Autoantibodies against ox-LDL (gamma ox-LDL), on the other hand, are not only measurable in the blood but may also reflect the extent of in vivo oxidation of native LDL and provide any early sign of risk for atherosclerosis. Current assay for gamma ox-LDL needs improvement. Routine clinical application of this assay has to wait until all parameters of this assay are defined and characterized.

Protein digest analysis by pressurized capillary electrochromatography using an ion trap storage/reflectron time-of-flight mass detector

Pressurized capillary electrochromatography (pCEC) has been coupled to an ion trap storage/reflectron time-of-flight mass spectrometer for the analysis of peptide mixtures and protein digests. Taking advantage of the electroosmotic flow, high separation efficiency has been achieved in pCEC due to a relatively flat flow profile and the use of smaller packing materials. A supplementary pressure was used in these experiments which suppressed bubble formation and also allowed the tuning of the elution of peptides using the electrical field. In this work, a fast separation of a six-peptide mixture has been successfully performed. Using columns only 6 cm long, a tryptic digest of bovine cytochrome c was fully separated in around 14 min by properly tuning the applied voltage and the supplementary pressure. In addition, relatively complex protein digests, such as a tryptic digest of chicken ovalbumin, were analyzed using this pCEC/MS system, and more than 20 peaks were resolved in the total ion current chromatogram within 17 min. The use of an ion trap storage/reflectron time-of-flight mass spectrometer as an on-line detector further increased the resolving power of the pCEC by unambiguously identifying coeluting components. The nonscanning property of the time-of flight mass analyzer and the ion signal integration capability of the ion trap were successfully combined to provide rapid and sensitive full-mass range detection in these experiments.

Use of a polybrene capillary coating in capillary electrophoresis for rapid analysis of hemoglobin variants with on-line detection via an ion trap storage/reflectron time-of-flight mass spectrometer

A polybrene capillary coating in capillary electrophoresis (CE) has been used for rapid analysis of hemoglobin variant digests. The use of the polybrene capillary coating has allowed sufficient separation to resolve the large number of digest products formed upon tryptic digestion of the whole protein, so that prior separation of the hemoglobin alpha and beta chains is not required. The resolution of the digest peaks obtained by CE is sufficient so that even single amino acid substitutions can easily be detected using UV absorption detection. The digest is further analyzed by capillary electrophoresis separation with on-line detection using electrospray ionization interfaced to the ion trap storage/reflectron time of flight device (CE/ESI-IT/reTOF), where a comparison of the total ion electropherograms and mass spectra of the mutant and normal hemoglobins can detect the presence of a mutation site. The CE separation and mass analysis can be accomplished in typically 10-15 min. The unique capability of the CE/ESI-IT/reTOF system for detection of fast separations with narrow peaks that may be under 1 s fwhm is demonstrated. The speed of this system is essential for resolution of the large number of peaks that are separated in a short time duration using CE separations.

Hyperhomocyst(e)inemia is associated with impaired endothelium-dependent vasodilation in humans

BACKGROUND

Hyperhomocyst(e)inemia is a risk factor for atherosclerosis and is prevalent in the elderly. The objective of this study was to determine whether hyperhomocyst(e)inemia is associated with impaired endothelium-dependent vasodilation in humans.

METHODS AND RESULTS

High-resolution vascular ultrasonography was used to study endothelium-dependent and -independent vasodilation in a nonatherosclerotic peripheral conduit artery of 26 elderly hyperhomocyst(e)inemic subjects and 15 age- and sex-matched subjects with normal homocysteine levels. Flow-mediated, endothelium-dependent (nitric oxide-mediated) vasodilation was assessed by measuring the percent change in brachial artery diameter during reactive hyperemia. Endothelium-independent vasodilation was assessed after the administration of 0.4 mg sublingual nitroglycerin. Endothelium-dependent vasodilation was significantly impaired in the hyperhomocyst(e)inemic subjects compared with control subjects (3.7 +/- 0.6% versus 8.1 +/- 1.2%; P = .004), whereas endothelium-independent vasodilation was not different between the two groups (10.1 +/- 1.6% versus 9.3 +/- 1.5%; P = NS). In a linear regression analysis with serum homocysteine concentration, folic acid, age, sex, cholesterol (serum total, LDL, or HDL cholesterol), mean arterial blood pressure, use of antihypertensive medication, and baseline brachial artery diameter included as covariates, serum homocysteine concentration emerged as the only significant predictor of flow-mediated vasodilation.

CONCLUSIONS

These data indicate that hyperhomocyst(e)inemia is associated with impaired endothelium-dependent vasodilation in humans and suggest that the bioavailability of nitric oxide is decreased in hyperhomocyst(e)inemic humans.

Open-tubular capillary electrochromatography with an on-line ion trap storage/reflectron time-of-flight mass detector for ultrafast peptide mixture analysis

In this work, a novel open-tubular column (OTC) capillary electrochromatography (CEC) system has been coupled to an on-line ion trap storage/reflectron time-of-flight mass spectrometer for ultrafast peptide mixture analysis. Reversed-phase OTCs prepared by the sol-gel process were coated with an amine, which greatly enhanced the electroosmotic flow in an acidic buffer solution and considerably reduced nonspecific adsorption between the peptides and the column wall. A six-peptide mixture could be separated to baseline within 3 min on this system. A full mass range detection speed of 8 Hz was used in all these experiments, which was sufficiently rapid to maintain the high efficiency of ultrafast separations. Because of the high duty cycle of the mass spectrometer and the column path length-independent concentration-sensitive feature of the electrospray ionization process, high-quality total ion chromatograms could be obtained with injections of only 1-2 fmol of peptide samples. A concentration limit of detection of 1 x 10(-6) M was also achieved due to the preconcentration capability of CEC. In addition, a novel gradient CEC device was demonstrated which did not result in a pressure-driven flow. A tryptic digest of horse heart myoglobin was successfully separated on the gradient CEC system within 6 min. The use of the mass spectrometer increased the resolving power of this system by clearly identifying coeluting components.

The use of on-line capillary electrophoresis/electrospray ionization with detection via an ion trap storage/reflectron time-of-flight mass spectrometer for rapid mutation-site analysis of hemoglobin variants

Capillary electrophoresis/electrospray ionization using an ion trap storage/reflectron time-of-flight mass spectrometer detector (CE/ESI-IT/reTOF) is used to provide a rapid and sensitive method for analyzing structural variants in the hemoglobin (Hb) beta-chain. The Hb alpha- and beta-chains are separated and the beta-chain is digested by trypsin. The digest is analyzed by CE/ESI-IT/reTOF where a comparison of the total ion electrophorograms and mass spectra of the mutant and normal hemoglobins (Hbs) can detect the presence of a mutation site. In addition, collision-induced dissociation in the vacuum interface-skimmer region can be used to pinpoint the identity of such a site. The unique capability of the CE/ESI-IT/reTOF system for accurately detecting fast separations with narrow peaks that may be under 1 s full width at half maximum is demonstrated. The speed of this system is essential for resolution of the large number of peaks that are separated in a short time duration using CE separations.

Development of a capillary high-performance liquid chromatography tandem mass spectrometry system using SWIFT technology in an ion trap/reflectron time-of-flight mass spectrometer

In this work a capillary high-performance liquid chromatography/tandem mass spectrometry system has been developed in a quadrupole ion trap/reflectron time-of-flight mass spectrometer. The broadband excitation for isolating a precursor ion is achieved by generating the stored waveform inverse Fourier transform waveform in real time. Following the isolation and cooling periods, an auxiliary AC voltage (tickle) is applied to the entrance end cap of the ion trap to generate collision induced dissociation. The amplitude of the tickle voltage is optimized on-line using a feedback method which involves having two computers communicating with each other. This system has been tested with a 4-peptide mixture and tandem mass spectra were obtained for each peptide.

[Nasopharyngoscopic analysis of the velopharyngeal function in normal and cleft lip and palate patients]

The speech problem in patients born with cleft lip and palate is mainly due to the insufficiency of the velopharyngeal (VP) valving mechanism, manifested as in visually seen nasal emission, and auditorily perceived hypernasality and articulation disorders. Evaluations of resonance and VP function can be conducted by: (1) perceptual rating scale based on speech pathologist's subjective judgement and (2) objective instrumental assessment, by the use of specific instrument. Nasopharyngoscopy has been commonly used clinically to diagnose VP function. The purpose of this study is: using nasopharyngoscopy to investigate the differences in VP mechanism between those with VP competence and VP incompetence in the dimension of velar displacement, lateral pharyngeal wall (LPW) displacement, degree of VP closure and pattern of VP closure. Ninty-eight subjects were studied from June 1990 to August 1991. They were divided into 4 groups: (1) group 1: normals with normal speech; (2) group 2: cleft of lip only, with normal speech; (3) group 3: cleft palate without nasal emission, but normal articulation; (4) group 4: cleft palate with nasal emission, with or without articulation error. Age range was from 6-47 years old with equal sex distribution. Ten Chinese sentences were used for standard test sentences, and were grouped according to Mandarin phonological distinctive features into 5 categories: (1) nasals; (2) vowels; (3) plosives; (4) fricatives/affricates; (5) connected number counting. The result indicates that the insufficient velar displacement to contact posterior pharyngeal wall is a determining factor causing velopharyngeal insufficiency in group 4; however, the lateral pharyngeal wall movement is not significantly different among 4 groups. Coronal pattern of velopharyngeal closure is the most common pattern among 4 groups of speakers.

Use of an ion trap storage/reflectron time-of-flight mass spectrometer as a rapid and sensitive detector for capillary electrophoresis in protein digest analysis

An ion trap storage (IT)/reflectron time-of-flight mass spectrometer (reTOFMS) has been coupled to capillary electrophoresis (CE) via a sheathless microelectrospray ionization method. This hybrid mass spectrometer has proved to be a rapid and sensitive detector for CE, where mass spectra could be acquired at a speed sufficient to maintain the high-resolution capabilities of CE separations. The nonscanning property of the time-of-flight mass analyzer can provide a full mass range spectral acquisition speed of up to 25 spectra/s with a data system developed in our laboratory. For the work reported herein, a spectral acquisition speed of 4 spectra/s was found to be optimal for maintaining the quality of the separation while achieving high sensitivity. Tryptic digests of bovine cytochrome c and beta-lactoglobulin A were analyzed using the CE/IT/reTOFMS combination, resulting in total ion electropherograms similar to those obtained using UV absorption detection. Taking advantage of the ion storage capability of the ion trap, a detection limit in the lowfemtomole range was routinely obtained for these digests using the total ion electrophoretic mode and CE capillaries of typical dimensions (41 microns i.d.). This high sensitivity was achieved while maintaining a resolution of approximately 1500 for mass identification using the capabilities of the IT/reTOF device. Due to the high acquisition speed and the mass discrimination capabilities of the mass detector, all the peaks in the total ion electropherograms, including some totally or partially unresolved peaks, could be unambiguously identified.

Encoding operation and transcoding as the major loci of the frequency effect

The present study used a lexical naming task as well as a regular naming task and a lexical decision task for locating the frequency effects in lexical decision and naming. The naming of Chinese characters in the lexical naming task (pseudocharacters also presented as in the lexical decision task) involves decision processes, while they are absent in the regular naming task. Since naming a Chinese character necessarily involves lexical access, a decision component of the frequency effect in lexical decision can be isolated. This procedure will not work for alphabetic orthographies, because sublexical processes underestimate the frequency effect in the regular naming task. As a consequence, not only can a prelexical component of the frequency effect in lexical decision be estimated, but a postlexical component of the frequency effect in naming can be estimated.

Nasopharyngoscopic evaluation and cephalometric analysis of velopharynx in normal and cleft palate patients

The velopharyngeal dimensions and velopharyngeal functions of 58 patients having a cleft lip and palate were compared with those of 30 normal noncleft subjects. The patient group received perceptual speech assessment, nasopharyngoscopic examination, and lateral cephalogram, and was classified accordingly into three categories: velopharyngeal competency, borderline velopharyngeal competency, and velopharyngeal incompetency. The results indicated that (1) the need ratio differs significantly among the three cleft palate patient groups and (2) when compared to the control group, the velopharyngeal incompetency group has an excessive need ratio, narrower posterior pharyngeal wall, narrower linear dimensions in pharyngeal depth, and shorter velar and hard-palate length. The clinical implication and application of the findings are discussed.

Advanced glycation end product (AGE): characterization of the products from the reaction between D-glucose and serum albumin

We incubated bovine serum albumin (BSA) with glucose in an attempt to study how the advanced glycation end products (AGEs) are formed and what methods can be used for their identification and isolation. The reaction was monitored by boronated affinity gel, size exclusion and ion exchange chromatography, and chromatofocusing. Reaction products were also characterized by fluorescence measurement, fructosamine assay, and polyacrylamide gel electrophoresis (PAGE). Based on the measurement of AGE-associated fluorescence (excitation, 370 nm; emission, 440 nm) we found that the AGEs could be detected as early as after 3 days incubation. The fluorescence was always associated with the larger molecules of cross-linking product resulting from the reaction between BSA and glucose. The overall fluorescence intensity increased with incubation time and fluorescence of the highest intensity was found with the AGE product largest in size. As with the Amadori product, AGEs also bind to the boronated gel column but with an even higher affinity. Compared to the original albumin monomer AGE molecules are not only larger in size but also have lower isoelectric points and carry more negative charges. Both the size and the negative charges of AGEs continue to increase over time during incubation. This results in a group of cross-linking molecules heterogeneous in size and charge. These results will aid in both the isolation and selection of appropriate AGE molecules for the preparation of anti-AGE antibodies, calibrator, and control in the development of an AGE immunoassay.

The development of a data system for a combination of liquid chromatography or capillary electrophoresis with an ion trap storage/reflectron time-of-flight mass detector

A data system based upon a 200 MHz transient recorder interface card in a Pentium PC computer is demonstrated for on-line analysis of microbore high-performance liquid chromatography (HPLC), capillary HPLC and capillary electrophoresis (CE) separations using a fast and sensitive ion-trap storage/reflectron time-of-flight mass spectrometric detector (IT-reTOFMS). Under the control of a user-written program, the system is capable of conducting the data acquisition and storage for a minimum of 30 min, at rates exceeding 10 Hz, of individual mass spectra containing 16,000 data points having 10 nsec resolution. The capability is mainly attributed to the use of a data reduction scheme in which only mass intensities higher than a preset threshold are saved as indexed flight-time/intensity pairs. This produces a typical reduction ratio of 30:1 in data set size, yielding faster storage with smaller file size, and permits the complete set of mass spectra to be held in the computer's memory. In addition, the data system is capable of displaying, for real-time evaluation of the analysis, each individual mass spectrum and the total-ion chromatogram. Further, the selected-ion chromatograms of given masses and a 3-dimensional topographic map describing a separation process can be rapidly generated from the collected data for the unambiguous and high fidelity identification of target analytes in a complex mixture.

Identification and characterization of c-erbB-2 proteins in serum, breast tumor tissue, and SK-BR-3 cell line

We have identified and characterized c-erbB-2 protein molecules in sera from patients with carcinomas, in both cytosol and cell membrane extract from breast tumor tissue and in both the culture medium and cell extract of the SK-BR-3 cell line. These proteins were characterized by various chromatographic techniques and identified by the use of two immunoassays; one measures both the c-erbB-2 oncoprotein (p185) and its ectodomain (p120), and the other in-house assay reacts specifically for p185. We found that the majority of the immunoreactivity detected in the serum, tumor tissue cytosol, and conditioned cell medium was derived from the ectodomain molecule (p120) of the c-erbB-2 oncoprotein (p185), whereas only p185 was detected in the extracts from cell membrane of both tumor tissue and the SK-BR-3 cell line. The ectodomain molecules (p120) found in the serum, cytosol, and cell medium were very similar in terms of molecular size and charge property. The molecular weight was determined to be 120 kDa by the size exclusion HPLC method. Both p120 and p185 are glycoproteins and were retained by the ConA Sepharose column. Both molecules are also heterogeneous in charge and multiple peaks could be identified in the elution profiles of anion exchange HPLC and chromatofocusing. This information should not only facilitate the isolation of these molecules, but also improve preparation of specific antibodies, preparation of calibrators, and development of improved assays for these proteins.

Measurement of c-erbB-2 proteins in sera from patients with carcinomas and in breast tumor tissue cytosols: correlation with serum tumor markers and membrane-bound oncoprotein

Using a commercial kit with antibodies against the ectodomain of c-erbB-2 protein, we detected c-erbB-2 immunoreactivity in human serum. We found that the percentages of patients with elevated serum c-erbB-2 immunoreactivities were 35, 21, and 9% in breast, prostate, and ovarian carcinoma, respectively. The majority of the elevated immunoreactivities were associated with sera containing highly elevated tumor markers with the highest in breast carcinoma (35%) and lowest in ovarian cancer (9%). Excellent correlations were also observed between the serum levels of c-erbB-2 immunoreactivity and the dominant tumor markers in serial specimens from individual cancer patients. We could also detect the c-erbB-2 immunoreactivity in the cytosols prepared from the breast tumor tissue for estrogen and progesterone receptor (ER & PgR) measurements using the same commercial kit for serum studies, and the intact c-erbB-2 oncoprotein (p185) in the extracts of the tissue membrane fractions with a different kit designed for tissue extract. The level of c-erbB-2 immunoreactivity in the cytosol from 124 human breast tumor specimens had an excellent correlation with the cell membrane concentrations of p185 (gamma = 0.89). Most of the elevated cytosol c-erbB-2 immunoreactivities were also found to associate with breast tumor specimens containing low concentrations of ER & PgR. It appears that measuring the c-erbB-2 immunoreactivity potentially could be used as a prognostic marker without performing tissue biopsies and also as a serum tumor marker for managing cancer patients.

Purification of PSA-ACT complex: characterization of PSA-ACT complex by various chromatographic procedures

We have explored various chromatographic procedures with the intention of establishing an isolation procedure that would allow us to isolate a large quantity of PSA-ACT (prostate specific antigen-alpha 1-antichymotrypsin) complex either from patients' sera or from incubation mixtures of free PSA and protease inhibitors. We found that at pH 7.2, both free PSA and PSA-ACT molecules are negatively charged and bind to the DEAE-Sepharose column. However, they could be separated from each other using a linear gradient of NaCl at pH 7.2. Both free PSA and PSA-ACT molecules were also found to be retained by the Con A Sepharose column because of the carbohydrate moiety of the PSA molecule. These two molecules were not separable by Con A chromatography. These two molecules apparently differ in their isoelectric points and were well separated by chromatofocusing using a pH gradient from pH 9 to 6. It appears that chromatofocusing can also be used to identify the isoforms of free PSA because of its high resolving power. The large difference in molecular size between free PSA and PSA-ACT complex allowed their separation by gel filtration chromatography on a column containing either S-100, S-200, or S-300 gel. S-200 gel appeared to be the best for the separation of free PSA from PSA-ACT and for the removal of other contaminating serum proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of free PSA isoforms, PSA complex formation, and specificity of anti-PSA antibodies by HPLC and PAGE-immunoblotting techniques

Both high performance liquid chromatographic (HPLC) and polyacrylamide gel electrophoresis-immunoblotting (PAGE-immunoblotting) procedures have been established for the study of isoforms of free prostate-specific antigen (PSA) and the complex formation between free PSA and protease inhibitors, and for the evaluation of the specificities of various anti-PSA antibodies. We found multiple isoforms of free PSA on PAGE, which were all capable of forming complexes with protease inhibitors. The same isoform pattern can be produced from the original seminal fluid. The PSA isoforms differ from each other most likely in charge because they could be converted to one band on SDS-PAGE and to a single peak by gel filtration chromatography. We found it difficult to form large quantities of PSA complex when mixing free PSA from seminal fluid with protease inhibitors, regardless of whether the free PSA or the protease inhibitors were in excess. Except for the PSA-ACT complex, which was consistently detectable by both HPLC and PAGE-immunoblotting techniques after incubation, these two procedures disagreed in their detection of PSA-A2M and PSA-AT complexes. The PSA-A2M complex was usually observable by immunoblotting techniques but barely detectable on HPLC, whereas PSA-AT was totally invisible by immunoblotting but appeared as a peak in the HPLC elution profile. Mixing free PSA with serum clearly resulted in both PSA-ACT and PSA-A2M complexes. However, more PSA-ACT than PSA-A2M was formed; the result was also confirmed by using 125I-PSA for mixing. PSA could be separated into active and inactive PSA by DEAE Sepharose chromatography with a 14-fold difference in protease activity. The difference in enzymatic activity apparently had no effect on complex formation. All the anti-PSA antibodies examined in this study reacted with PSA isoforms, PSA-ACT and PSA-A2M complexes. We conclude that it would be almost impossible to establish an assay to measure all forms of PSA in the serum and to expect to produce precise and accurate PSA values.

Development of a microplate ELISA for free PSA and PSA-ACT complex in serum

An ELISA on microplate was established for the total serum PSA. We selected the monoclonal antibody for the assay from commercial sources making certain that it reacted with both free PSA and PSA-alpha 1-antichymotrypsin (PSA-ACT) complex from human serum with similar affinity (so-called "equimolar"). We also chose a test format with polyclonal anti-PSA antibodies coated on the well and monoclonal anti-PSA antibodies for quantification to gain higher test sensitivity. Two different sample volumes from each specimen, 5 and 50 microliters, were used for the assay in order not only to further increase test sensitivity and improve precision at both low and highly elevated PSA concentrations, but also to widen the assay concentration range (0-500 ng total PSA per ml). Using two sample volumes also reduces any hook effect and shortens the turn-around time because repeated determinations are usually required when specimens contain highly elevated PSA concentrations. The use of pooled sera containing approximately 95% PSA-ACT complex and 5% free PSA as a calibrator allows for a close matching of the calibrator with serum specimens in immunoreactivity and PSA composition. Moreover, our assay shows no hook effect up to 15,000 ng/ml. The within-day precision (% CV) in the critical concentration range of 4-12 ng/mL is approximately 5%. The PSA values obtained from this assay correlate well with that of the Hybritech kit (gamma = 0.998, slope equals to 1.033), indicating that this kit can replace the Hybritech Tandem E PSA kit for serum PSA determination in clinical laboratories.

Correlation of serum concentrations of PSA-ACT complex with total PSA in random and serial specimens from patients with BPH and prostate cancer

The current assays for serum prostate specific antigen (PSA) have failed to produce the same PSA values on the same specimens because of problems with antibody specificity and calibrator preparation. To eliminate these problems, we proposed to replace the current serum PSA assay with an assay specific for the PSA-ACT (PSA-alpha 1-antichymotrypsin) complex in the serum. An assay specific for the PSA-ACT complex was established using the anti-PSA antibody to coat the microplate for capturing the PSA complex and anti-ACT polyclonal antibodies for quantification. There was an excellent correlation between serum concentrations of PSA-ACT and total PSA, using either the Hybritech calibrator (gamma = 0.996) or a serum calibrator prepared in house (gamma = 0.993), in random as well as in serial specimens from 14 individual patients. Even though we did not find a gradual increase in the percentage of PSA-ACT with the increase of total PSA in cancer patients, a slightly higher percentage of free PSA was measured in pooled normal sera (18%) and in pooled sera containing only 12 ng/ml of total PSA (12%), compared to serum pools containing elevated PSA (> 100 ng/ml) level, in which most PSA was in the complex form (95%). Therefore, using an assay that specifically measures the PSA-ACT complex in the serum not only simplifies the preparation of calibrator but eliminates the difficulty of antibody selection, it also allows various assay kits to produce identical PSA values and also improve the test specificity for prostate cancer.

PSA immunoreactivity detected in LNCaP cell medium, breast tumor cytosol, and female serum

We made an effort to identify a reliable source for obtaining large quantities of both free (PSA) and PSA-ACT complex for the preparation of the calibrator for the PSA assay. Using size exclusion chromatography, we found both free PSA and PSA-ACT complex in the conditioned cell medium of the LNCaP cell line, which was derived from a human metastatic adenocarcinoma of the prostate. An assay specific for PSA-ACT reacted only with the PSA-ACT complex from cells grown in serum-free medium, and not with the complex from the cell medium grown in 10% calf serum. We also found both free PSA and PSA-ACT complex in 15% of cytosols prepared from breast tumor tissues; the cytosol PSA concentrations ranged from 0.1 to 110 ng/ml. No correlation was found between cytosol PSA and concentrations of estrogen receptor, progestin receptor, epidermal growth factor receptor, cathepsin D, or the ectodomain of c-erbB-2 protein. Based on chromatographic characterizations and the slope of their dose-response curves, it appears that both free PSA and PSA-ACT complex found in the cytosols are similar to PSA complex from the cell medium and the serum of prostate cancer patients. Ectopic PSA was also detected in pooled sera from patients with breast, ovarian, pancreatic, and colon carcinoma. The PSA concentrations in these serum pools increased with the level of their dominant tumor marker. In any event, the LNCaP cell medium appears to be a reliable source for obtaining both free and ACT-complexed PSA of human tumor origin for the preparation of PSA assay calibrators.

Correction of secondary velopharyngeal insufficiency in cleft palate patients with the Furlow palatoplasty

To avoid the serious complications of pharyngeal flap surgery, a Furlow palatoplasty was used to correct velopharyngeal insufficiency after primary palatoplasty in 18 Chinese cleft palate patients (3 to 23 years old) from 1988 to 1992. The follow-up duration was 1 to 4 years. These patients were selected after a complete study for velopharyngeal insufficiency, including intraoral examination, perceptual speech assessment, videonasopharyngoscopy, and/or multiview videofluoroscopy. The criteria for selection included age, pattern of velopharyngeal closure, size of the velopharyngeal gap, extent of lateral pharyngeal wall movement, existence of a Passavant's ridge, and abnormal levator veli palatini muscle insertion. Complete velopharyngeal closure was achieved for 16 patients after surgery. The majority of these patients (15) had a velopharyngeal gap less than 5 mm. The 2 patients who still had velopharyngeal insufficiency after the surgery had a velopharyngeal gap larger than 10 mm before the surgery. The most important factor seemed to be the size of the velopharyngeal gap. Pattern of velopharyngeal closure or age of the patient also might play an important role. The results showed that a Furlow palatoplasty can satisfactorily correct velopharyngeal insufficiency in carefully selected patients. Although the criteria for the selection of this operation need further study, present results are encouraging.

Assay for prostate specific antigen (PSA): problems and possible solutions

The absolute tissue specificity of prostate specific antigen (PSA) allows the use of PSA test not only for detecting recurrence or metastasis at an early stage after radical prostatectomy but also for screening prostate cancer if combined with digital rectal examination. There is also a need to improve the current PSA test to better differentiate between prostate cancer and benign prostate hyperplasia (BPH). Because of these clinical applications, a much greater demand was placed on PSA test for extra sensitivity, accuracy, and precision even within the normal PSA concentration range. However, the current commercial assay kits for PSA do not provide correct PSA values. Many factors contributing to the problem include the specificity of the anti-PSA antibodies, the composition of the calibrator, the PSA values assigned to the calibrator, the PSA isoform used for anti-PSA antibody preparation, the test design, and the composition of the diluent. Most problems were derived from the failure of realizing earlier that the majority of the PSA exists in serum not as free PSA but as complexes with protease inhibitors. Other problems, such as constantly changing composition of various forms of PSA in serum specimens, and different clearance rates for various forms of PSA make almost impossible to develop an ideal assay for PSA. Therefore, we suggest that test should be designed for measuring PSA-ACT (PSA-alpha 1-antichymotrypsin) complex only. Changing the focus from the measurement of total PSA of various forms to the PSA-ACT complex alone may improve the differentiation between prostate cancer and BPH but may also simplify the selection of anti-PSA antibodies and the preparation of calibrator for the assay.

Comparison of neural network and k-NN classification methods in medical image and voice recognitions

We make a comparison of classification ability between BPN (Back Propagation Neural Network) and k-NN (k-Nearest Neighbor) classification methods. Voice data and patellar subluxation images are used. The result was that the average recognition rate of BPN was 9.2 percent higher than that of the k-NN classification method. Although k-NN classification is simple in theory, classification time was fairly long. Therefore, it seems that real time recognition is difficult. On the other hand, the BPN method is long in learning time but is very short in recognition time. Especially if the number of dimensions of the samples is large, it can be said that BPN is better than k-NN in classification ability.

Identification and characterization of microcystin-LY from Microcystis aeruginosa (strain 298)

Two toxins, a main component A and a minor component B, were isolated from the freshwater cyanobacterium Microcystis aeruginosa (strain 298) and characterized in their chemical structure by amino-acid analysis, configurational analysis, by FAB-MS and 1H-NMR spectroscopy. The acid hydrolysate yielded for toxin A as constituent amino acids D-Ala, L-Leu, D-Glu, erythro-D-beta-Me-Asp and L-Arg, and for toxin B the amino acids D-Ala, L-Leu, D-Glu, erythro-D-beta-Me-Asp and L-Tyr. 1D and 2D 1H-NMR spectroscopy of the toxins A and B in DMSO-d6 allowed to characterize them as cyclic heptapeptides containing both the unusual beta-amino acid Adda (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid) and N-methyldehydroalanine (Mdha) as additional constituent residues. Toxin A was found to correspond to the known and structurally well characterized microcystin-LR and toxin B to microsystin-LY. The presence of this variant has already been proposed, but its primary structure could be confirmed in this study.

[Alternative combination chemotherapy with mitomycin C, vincristine, methotrexate, 5-fluorouracil, cis-platinum and adriamycin for adenocarcinoma of the lung]

Efficacy of an alternative combination chemotherapy with MMC, VCR, MTX, 5-FU, CDDP and ADM for adenocarcinoma of the lung is reported. Forty-one advanced cases (stage III: 9; IV: 32) were chosen for the chemotherapy. Two combination chemotherapies MMC + VCR + MTX + 5-FU + CDDP: MVMFP; MMC + VCR + MTX + 5-FU + ADM: MVMFA were repeated alternatively for 8 consecutive weeks with 2 interposed rest weeks, and this regimen was completed in 34 cases. All 41 cases were evaluable. Three and 26 cases achieved complete and partial responses, respectively. The response rate was 70.7%, and the median survival time was 13 months. The adverse effects of the chemotherapy observed were tolerable: alopecia (63.4%), gastrointestinal symptoms (14.5%), bone marrow toxicity (12.2%) and liver dysfunction (4.8%). These results indicate that our MVMFP/MVMFA alternative chemotherapy is quite effective for adenocarcinoma of the lung, comparable or superior to conventional chemotherapies.

Advanced glycosylation end products: a new disease marker for diabetes and aging

Advanced glycosylation end products (AGEs) are a potentially useful marker for monitoring glycemic control, predicting the risk of diabetes- and aging-associated clinical complications, and monitoring the treatment of patients with micro- and macrovascular diseases, including retinopathy, atherosclerosis, nephropathy, and neuropathy. AGEs or AGE-proteins are derived from nonenzymatically glycated proteins (Amadori products) after further cross-linking with other proteins and additional rearrangement. AGE-proteins can be assayed by either radioreceptor or immunoassays in blood and tissues. No commercial kit is available at this time.

Detection of the extracellular domain of c-erbB-2 oncoprotein in sera from patients with various carcinomas: correlation with tumor markers

Using a serum enzyme immunoassay (EIA) kit from Triton diagnostics we detected c-erbB-2 oncoprotein activity in random sera containing highly elevated tumor markers and also in serial specimens from cancer patients expressing elevated oncoprotein activities. Elevated oncoprotein activity was found not only in sera of breast and ovarian carcinomas but also in sera from colorectal, pancreatic, and prostate carcinomas and even from primary hepatoma. Whenever oncoprotein was overexpressed in an individual patient, there was usually an excellent correlation between the oncoprotein activity and the level of dominant tumor marker in serial serum specimens. Based on the size exclusion S-200 column chromatography, we found only a single molecule containing c-erbB-2 oncoprotein activity in pooled sera from cancer patients whereas two oncoproteins slightly different in size were detected in breast tumor tissue cytosol. Using HPLC on a Superose 12 HR column, the serum portion of the oncoprotein was eluted at a position near IgG, suggesting that the extracellular domain of the oncoprotein exists as a dimer in the serum.

Development of radioimmunoassays on microplate: application for CA-GI and CA-Br tumor markers

By taking advantage of a newly available microplate counter for radioactivity and the organic solvent-resistant, pigmented microplates, we have successfully established radioimmunoassays (RIA) for both CA-GI and CA-BR on microplate for routine clinical use. In the process of assay development, we found that both pigmented PicoPlate, made of acrylonitrile, and polystyrene Microlite 2 can be coated with antialpha fetoprotein (AFP) and antinerve growth factor (NGF) and used for setting up immunoassays for AFP and nerve growth factors. There were no problems following a test format of either competitive binding or sandwich design. Microlites 2 is recommended over PicoPlate because Microlites 2 is made of polystyrene, which is less expensive and separable into 8-well strips or even single wells. Single-well separation allows for the use of regular gamma counters in case Topcount is unavailable. We also found that the sensitivity of these tests was not significantly affected even though Topcount counts the weaker beta emissions. Similar dose-response curves could also be generated between original Biomira tube assays and assays using PicoPlate or Microlite 2 coated with protein antigens CA-Br and CA-GI. Excellent correlations were also obtained between the microplate assays and the Biomira tube assays for CA-GI and CA-Br using groups of serum specimens from cancer patients. We recommend the development of various RIAs on the microplate: it requires less reagents and less sample handling by the technologists and it can be essentially automated.

Review of diabetes: identification of markers for early detection, glycemic control, and monitoring clinical complications

The hallmark of diabetes mellitus, whether type I or type II, is hyperglycemia. Clinical complications associated with diabetes are most likely the consequence of hyperglycemia via both altered metabolic pathways and nonenzymatic glycation of proteins. The nonenzymatic glycation of proteins is accelerated in diabetes due to elevated blood glucose concentration. The Amadori product of nonenzymatic glycation will further cross-link with other proteins to form advanced glycosylation end products (AGEs). The reaction of AGEs with long-lived proteins, such as collagen, and the uptake of AGEs by the receptors on macrophages, endothelial cells, and platelets are major reasons for the development of various clinical complications in diabetes. Several markers have been identified for the screening, diagnosis, and monitoring of the disease. Autoantibodies against beta cells are the best markers for mass screening and for early detection of type I diabetes. In addition to glycated hemoglobin, AGEs and blood glycated proteins of various half-lives could be used for monitoring glycemic control. Several abnormal metabolites have been identified as potential markers for monitoring the severity of various clinical complications. The most interesting findings in diabetic markers could be AGEs. The amount of AGEs found in the tissues could be related to the extent of micro- and macrovascular damage and might prove useful for monitoring the treatment of patients at early stages of either nephropathy, atherosclerosis, retinopathy, or neuropathy.

Rhabdomyosarcoma cell line can be used for the isolation of soluble acetylcholine receptor and for assaying blocking and modulating autoantibodies

We found that the Rhabdomyosarcoma (RD) cell line expresses human acetylcholine receptor (AChR) based on the following evidences: 1. Soluble AChR can be isolated from RD cells following the isolation procedure for AChR from human muscle; 2. Intact RD cells bind to alpha-bungarotoxin (alpha Butx) in a time-dependent and saturable fashion. The apparent dissociation constant (5.3 x 10(-10) M) is very similar to that reported for TE671 cells, which is known to express AChR; 3. Like fresh muscle culture, RD cells not only bind but also internalize 125I-alpha Butx. Soluble AChR from RD cells can be labeled specifically with 125I-alpha Butx and then used to quantify binding autoantibodies in myasthenic patients. We also demonstrate that blocking antibodies can be detected in sera from patients with myasthenia gravis (MG) using RD cells and the ability of RD cells to internalize alpha Butx. Consequently, RD cells can be used as a reliable source for obtaining soluble AChR and as a replacement for rodent or human muscle cultures in measuring blocking and modulating antibodies.

The long-term modality effect: in search of differences in processing logographs and alphabetic words

The visual superiority effect (a reverse long-term modality effect) has been consistently found with Chinese logographs. For its explanation in terms of script differences, it has been believed that lexical access is more direct or quicker for Chinese logographs than for alphabetic words. It has also been believed that Chinese logographs are more unique in shape or more discriminable than alphabetic words. Finally, Chinese logographs have been considered to facilitate recall through their graphic features that classify Chinese words into categories. The results of Experiments 1-5 show that these three assumptions can be ruled out. The results of Experiments 6-10, on the other hand, support the long-term priming interpretation of the visual superiority effect, which explains (a) why the visual superiority effect can be consistently obtained for recall of Chinese words by Chinese subjects, (b) why the effect cannot be consistently obtained for recall of English words by Western subjects, (c) why the effect can be also obtained for recall of English words by Chinese subjects, (d) why the effect can be easily obtained for recall of a set of words, but not for recall of a different set of words by Chinese subjects, and (e) why the effect can be easily obtained from Chinese subjects speaking a dialect that is different from Mandarin.

Chromatographic characterization of CA 19-9 molecules from cystic fibrosis and pancreatic carcinoma

We have compared the size, the binding to Concanavalin A (Con A), and the affinity for monoclonal antibody 1116NS-199 (Mab 19-9) among CA 19-9 molecules from sera of cystic fibrosis (CF) and pancreatic carcinoma patients and from sputum extracts. CA 19-9 molecules of two different sizes were found in all types of specimens by Sepharose 4B chromatography. While the smaller CA 19-9 molecule was predominant in CF patient sera, the larger molecule was associated with most of the sera from patients with pancreatic carcinoma. The majority of the sputum extracts contained the larger CA 19-9 molecule. All CA 19-9 molecules studied by Con A chromatography did not appear to bind to Con A, and almost 100% were found in the nonreactive fraction. The CA 19-9 molecules from sera of either CF or pancreatic carcinoma patients exhibited variable affinities for Mab 19-9, some approaching that of the standard curve but many also having lower affinities. The lowest affinity was displayed by CA 19-9 molecules from the sputum extract. It appears that development of more specific assays for CF and for carcinoma is possible if the correct CA 19-9 molecule is selected for antibody preparation and for use as standards.

Low frequency and low level of elevation of serum CA 72-4 in human carcinomas in comparison with established tumor markers

We evaluated a new circulating tumor marker, CA 72-4, by comparing its frequency of appearance and level of elevation with other established tumor markers in serial serum specimens from patients with various carcinomas. We found that CA 72-4, though highly expressed and widely found in various tumor tissues, is present at low concentration and frequency in the serum. In breast, colon, ovarian, and pancreatic carcinomas, only 21%, 30.9%, 16%, and 26.5% of specimens, respectively, showed elevated CA 72-4. When elevated, the level of elevation was also low, much lower than that of the dominant markers. Poor response of CA 72-4 to therapy was especially noticeable in serial specimens. In most cases, the CA 72-4 remained normal for the entire series while other markers remained at elevated levels. However, changes of the level of CA 72-4 usually paralleled those of other markers but at a much lower concentration. Simultaneous measurement of CA 72-4 and CA 19-9 appears useful to differentiate colorectal from pancreatic carcinomas when they all contained elevated levels of CA 19-9. There was a much higher ratio of CA 72-4 to CA 19-9 with colon than with pancreatic and other carcinomas (247 +/- 524 vs. 4.7 +/- 6.8).

Conversion of a qualitative screening test to a quantitative measurement of urinary cystine and homocystine

Qualitative urinary screening procedures were converted to quantitative methods for urinary cystine and homocystine based on the reactions between these amino acids and cyanide-nitroprusside reagents. Cystine and homocystine are quantified by the measurement of absorbances at 521 and 524 nm, respectively. Cyanide-nitroprusside reacts with both cystine and homocystine. However, in the presence of silver nitrate, only homocystine reacts to produce a magenta color. Following the cyanide-nitroprusside reaction, absorbance must be read within three minutes for cystine and immediately for homocystine. The stability of the absorption spectra has no apparent effect on these quantitative assays. Amino acid concentrations are expressed as ratios to creatinine, which tends to eliminate false negative results in dilute urine specimens. The normal urine value for cystine and homocystine combined is 66.8 +/- 52 (n = 50) mg per g creatinine. The normal value for homocystine alone is 29.9 +/- 16.8 (n = 24) mg per g creatinine. The simplicity of these procedures allows these quantitative methods to be used as screening tests for cystinuria and homocystinuria.

Tumor markers CA 19-9 and CA 195 are also useful as markers for cystic fibrosis

When monoclonal kits are used we can no longer detect highly elevated serum concentrations of carcinoembryonic antigen in cystic fibrosis (CF) patients as we could earlier (Pediatr Res 10:223-236, 1975). Instead, we find increased concentrations of CA 19-9 or CA 195 in the CF sera. The serum levels of CA 19-9 not only reflect the pulmonary condition of CF patients but also respond well to antibiotic therapy. Several lines of evidence suggest that the elevated serum concentration of CA 19-9 is derived from sputum and corresponds with the amount of sputum in the lung. Correlations between CA 19-9 and CA 195 in random and serial specimens from both patients with CF and patients with pancreatic carcinoma suggest that all sera contain heterogeneous, Lewis blood group-related epitopes and the proportions of various epitopes are different among individual patients. When monitored on multiple tumor markers, the pattern of CF is different from that of pancreatic carcinoma although both usually show elevated CA 19-9. Our study indicates that both CA 19-9 and CA 195 can be used as sensitive markers for the early detection of exacerbation in CF patients.

Variation of geosmin content in Anabaena cells and its relation to nitrogen utilization

The addition of the proper amount of ammonium to the culture medium containing nitrate as nitrogen source enhanced the growth rate of Anabaena viguieri. The amount of geosmin produced by these cells varied with the concentrations of ammonium added. A negative correlation between the amount of geosmin produced and of the growth rate of cells was revealed. This was also found in cells grown on various forms of nitrogen sources. Without supply of any nitrogen compound, this organism is capable of fixing gaseous nitrogen, and under these conditions the cells grew relatively slowly. However, they produced more geosmin (per unit protein mass) than cells grown in the presence of combined nitrogen. The isolation of heterocysts, in which nitrogen was fixed, showed that these cells produced higher amounts of geosmin than vegetative cells. The possible relation of nitrogen assimilation to the production of geosmin in the cells was discussed.

Ca(2+)-insensitive modulation of a K+ conductance by inositol polyphosphates

Macrophages derived from phorbol ester-induced human leukemic (HL-60) cells exhibit a voltage-activated inward rectifying potassium conductance which was modulated by macrophage colony-stimulating factor (Wieland, S. J., Chou, R. H., and Gong, Q. H. (1990) J. Cell. Physiol. 142, 643-651). Roles of intracellular messengers in this regulatory mechanism were investigated. Intracellular dialysis with inositol 1,3,4,5-tetrakisphosphate (IP4) or inositol 1,4,5-trisphosphate during tight-seal whole cell recording produced a rapid increase in the inward rectifying conductance. Changes in intracellular Ca2+ levels alone did not reproduce the stimulatory effect of these modulators. Intracellular dialysis with guanosine 5'-O-(thiotriphosphate) (GTP gamma S) resulted in profound inhibition of this conductance. These data suggest a novel cellular function for inositol polyphosphates, particularly IP4, and show antagonistic modulation with GTP gamma S on a human macrophage inward rectifier.

Screening for inborn errors of amino acid metabolism

Early diagnosis and treatment may prevent brain damage and mental retardation in young infants with inborn errors of amino acid metabolism. The abnormal blood and urinary amino acids and their metabolites are listed in two separate tables in association with each disorder to aid laboratories in making a diagnosis during screening. Because of recent developments and discoveries, more detailed descriptions and diagnostic approaches in phenylketonuria (PKU) variants and urea cycle deficiencies are also presented. The test procedures routinely used for screening inherited metabolic disorders are also described. These include five simple chemical tests to detect excessive metabolites and amino acids; a one dimensional thin layer chromatography (TLC) to screen urine for abnormal amino acid patterns; a two-dimensional TLC for semiquantitative identification of amino acids in both urine and blood; and a high performance liquid chromatographic (HPLC) method for quantitative identification of amino acids. In addition, both one- and two-dimensional chromatographies run on small thin layer cellulose plates, are introduced, modifications which save a great deal of time, labor, and reagents. A new automated HPLC system is introduced for the quantitation of both primary and secondary amino acids; the sensitivity and speed of this system is especially useful for screening large numbers of physiological fluids. It is recommended that both the urine and blood from the same patients be screened to ensure that a diagnosis is not overlooked.

Acetylcholine receptors from normal human muscle: concentration, purification, and use in radioreceptor assays for autoantibodies

We measured the concentration of acetylcholine receptor (AChR) in various normal human muscles, obtained at autopsy, in order to find a more reliable and convenient source than the amputated leg muscle from diabetic patients for the isolation of AChR. We found that human calf muscle contains the highest concentration of AChR, approaching the concentration of receptor required for the radioreceptor assay for autoantibodies in myasthenia gravis (MG). Because the amount of contaminant proteins in the receptor preparations affect the sensitivity and precision of the assay, various chromatographic techniques were tested to improve the purity of the receptor preparation. We found that both G-100 Sephadex and DEAE Sephacel chromatographies were effective in removing contaminant proteins. DEAE Sephacel chromatography is particularly useful because the procedure provides higher recovery of receptor. Against the same pool of autoantibodies from patients with MG, AChRs from diabetic and normal leg muscle exhibit similar affinities. We conclude that AChR from normal human calf muscle can be used in radioreceptor assays for measuring autoantibodies in patients with myasthenia gravis.

Effect of different test designs of immunoassays on "hook effect" of CA 19-9 measurement

Determining serum CA 19-9 using regular Centocor kit frequently requires numerous repeats when specimens contain highly elevated levels of CA 19-9. We found that the number of repeats could be reduced if the Centocor kit with an extended concentration range was used. Using an extended Centocor kit could also eliminate falsely low CA 19-9 results. However, when a Biomira RIA kit, based on a competitive binding principle, was used, falsely low CA 19-9 values could be completely avoided and, in most cases, only a single repeat was usually required to arrive at the true result. This is because the level of CA 19-9 in the specimen can be approximated from the radioactivity count. Therefore, when designing an immunoassay for tumor markers, one needs to take into consideration the concentration range of the tumor marker in the specimens if one would like to avoid repeats and falsely low values.

Internal consistency and factor structure of the Chinese Health Questionnaire

The internal consistency and factor structure of the Chinese Health Questionnaire (CHQ) were investigated in 2 samples in Taiwan, one from 3 communities (n = 1023) and the other from consecutive attenders for health screening in a general hospital (n = 386). Cronbach's alpha coefficients were calculated to be 0.84 and 0.83 for the 12-item and 0.90 and 0.92 for the 30-item CHQ version. Four factors similarly extracted for the CHQ-30 in both samples include somatic symptoms, anxiety and worrying, social dysfunction, and depression and poor family relationship. The implications of these findings were discussed from a cross-cultural perspective.

RU 486 interferes with egg transport and retards the in vivo and in vitro development of mouse embryos

Oral administration of RU 486 at 100 mg/kg BW/day to mice on Days 1 and 2 of pregnancy caused retention of embryos in the oviduct and expulsion of those having entered the uterus. The treatment also retarded the development of embryos. In vitro study showed that RU 486 reduced the percentage of 2-cell mouse embryos developing into blastocysts. Thus, in addition to interfering with egg transport and impairing embryonic development in vivo, RU 486 can act directly on the embryo, interfering with preimplantation development in vitro.

Serum alpha-fetoprotein and its lectin reactivity in liver diseases: a review

Increased serum concentration of alpha-fetoprotein (AFP) can be found in benign and malignant liver diseases, in yolk sac tumors, and in several nonhepatic neoplasms at advanced stage. The frequency and level of elevated serum AFP are highest in hepatocellular carcinoma (HCC) and yolk sac tumors. Most levels of serum AFP in HCC are greater than 500 ng per mL, whereas the serum AFP in most of the benign liver diseases is only moderately elevated and is transient in nature. Determination of lectin reactivity of serum AFP is helpful for the differentiation of HCC from other diseases associated with elevated serum AFP. Determination of Len culinaris agglutinin (LCA) reactivity of serum AFP is useful for the differentiation of HCC from benign liver diseases, and for early detection of hepatoma. Determination of concanavalin A (Con A) nonreactive AFP variant is useful for the differentiation of HCC from yolk sac tumors and may also allow for the differentiation of HCC from nonhepatic neoplasms. However, reaction with several lectins may be required if differentiation among various nonhepatic neoplasms is needed.

Conversion of pregnenolone to progesterone by mouse morulae and blastocysts

When mouse morulae, early blastocysts and implanting blastocysts were cultured with tritiated pregnenolone, tritiated progesterone and its metabolites, 5 alpha-pregnan-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnan-20-one, were isolated from the medium. It appears that mouse embryos can make progesterone from pregnenolone and the progesterone is quickly metabolized into various metabolites. These abilities increase with development. It is suggested that the mouse embryo can make progesterone and may regulate its own progesterone level for optimal development.

Metabolism of estrogens by rabbit blastocysts: formation of estrogen glucosides and preferential conversion of estrone to estradiol-17 beta

When day 6 rabbit blastocysts were cultured (3 embryos/mL) in medium 199 containing 3.68 microM estradiol-17 beta (E2), 40% of E2 was metabolized in 24 h, at a rate of 18 pmol/embryo(b)/h, yielding 4 major metabolite fractions. Two of them were identified to be estrogen glucosides: 17 beta-hydroxyestra-1,3,5(10)-trien-3-yl beta-D-glucopyranoside (E(2)3G) (12 pmol/b/h) and 17-oxoestra-1,3,5(10)-trien-3-yl beta-D-glucopyranoside (E(1)3G) (0.5 pmol/b/h). If the blastocysts were cultured in 3.68 microM E1 medium, 75% of E1 was metabolized in 24 h (34.1 pmol/b/h); most of it appears as E2 (8 pmol/b/h), E(1)3G (16 pmol/b/h), and E(2)3G (6 pmol/b/h). Thus, the 17 beta-hydroxysteroid dehydrogenase activity in the rabbit blastocysts catalyzes mainly in the direction of the E1----E2 conversion, with little or no E2----E1. This may be responsible in part for the faster metabolism of E1 than E2 by the rabbit blastocyst. In comparison with the rat, mouse, and hamster blastocyst, the rabbit embryo shows an additional capability to conjugate large amounts of estrogens into glucosides by steroid glucosyltransferase.

A rapid micro-scale procedure for determination of the total lipid profile

We describe a one-day micro-scale procedure for determining the total lipid profile. Only 0.55 mL of plasma is needed for complete quantification of total cholesterol (TC), triglyceride (TG), and all lipoproteins. After precipitation with dextran sulfate and magnesium, the high-density lipoprotein (HDL) fraction was separated by centrifugation in an Eppendorf microcentrifuge. Very-low-density lipoprotein (VLDL) was separated from low-density lipoprotein (LDL) plus HDL in a Beckman TL 100 ultracentrifuge. TC, TG, and cholesterol in different lipoprotein fractions were measured enzymatically in a Baker "Encore II" automated analyzer. CVs, both within-day and day-to-day, were less than 3% for TG and TC, and less than 5% for HDL-C determinations. CVs for LDL-C and VLDL-C were less than 7.5% and 15%, respectively. Results by our micromethods (n = 66) agreed well with those by the conventional methods used at the Northwest Lipid Research Center, which are standardized against the Reference Methods of the Centers for Disease Control. Coefficients of correlation between the two methods were 0.98 for TC, 1.0 for TG, 0.98 for HDL-C, 0.94 for LDL-C, and 0.96 for VLDL-C. Results of electrophoresis on agarose gel and radioactivity-recovery studies indicate that our micro-centrifugation and slicing procedures result in clean separation of VLDL from other lipoproteins.